Lathe tailstock device



Aug. 20, 1963 Filed Ma 19, 1958 A. M. LE LAN LATHE TAILSTOCK DEVICE 4 Sheets-Sheet 1 20, 9 A. M. LE LAN 3,101,019

LATHE TAILSTOCK DEVICE Filed May 19, 1958 4 Sheets-Sheet 2 0, 1963 A. M. LE LAN 3,101,019

LATHE TAILSTOCK DEVICE Filed May 19, 1958 4 Sheets-Sheet 3 om mm H .1 mm

MN Nu Aug. 20, 1963 A. M. LE LAN 3,101,019

- LATHE TAILSTOCK DEVICE Filed May 19, 1958 4 Sheets-Sheet 4 Fig.6

United States Patent 3,101,019 LATHE TAILrTGCK DEVICE Armand Marcel Le Ian, Vanves, France, assignor to H. Ernault-Batignolles A., Paris, France, a company or France Filed May 19, 1958, Ser. No. 736,224 Claims priority, application France May 20,1957 3 Claims. (Cl. 82--Z-5) The invention relates to machining, on a lathe, of mechanical parts made directly from a bar, and more particularly to a device for manipulating a bar passed through the hollow spindle of a headstock.

The difiiculties encountered during the machining of mechanical parts from a bar are known, particularly if the bar is relatively long. In particular, whipping of the bar is observed and it may, in addition, be subjected to flexure stresses due to the thrust of the tool. In order to overcome these disadvantages, a displaceable back-rest. is frequently provided, which supports the part behind the tool, but this accessory detracts from the ease and rapidity of production and ejection of the parts.

At the same time, it is difficult to control with precision the periodic advance movements of the bar, particularly in the case where the bar is positioned by a fixed stop, because of the stub end which is left on the bar after the parting oiI of the machined part. In order to avoid the rejects which would result from inaccurate feed, it is necessary to provide relatively large amounts of wastage on each part to be machined.

Finally, the lateral ejection of the machined parts is incompatible with a high rate of production, and it complicates the subsequent stockingof the parts or their transfer to other machines. i i

One of the objects of the invention is to obtain the. correct machining, on a lathe, of pants from bar, without whipping or flexure of the bar.

Another object of the invention is to effect the successive feed of the bar in a precise manner. i i

A further object of the invention is to eject each rnachined part automatically without it being necessary to have recourse to supplementary devices provided more particularly for this purpose. i

It is another object of the invention to provide a manipulation process consisting in holding the bar axially by means of a rotary gripping member mounted on the frame of the lathe in the extension of the spindle, allowing it to turn on itself while it is held in the chuck, releasing the chuck, displacing the bar coaxially by a given length, by means of the said gripping member, in the direction which moves said member away from the headstock, re-closing (the chuck, releasing the gripping member and returning it towards the headstock with at least one displacement through the said given length, the machining of the part being eflfected between the periods of displacement of the gripping member towards the headstock.

Still anotherobject of the invention is to provide a device for carrying out the-above process comprising, in combination, a support which is carried by the frame of the lathe in the geometrical axis of the spindle thereof,

agripping member for the bar, mounted in said support in such a manner a's tobe able to rotate and slide on the geometrical axis of the,hollowlathe-spindle, said support and said gripping memberbeing drilled axially, right through, of a diameter sufficient to permit the, passage 1 andejec'tion ot the machined parts, means for displacing saidgripPingmember. axiallyandtrneans adapted either to tighten said, gripping member on the bar in order to fix "thereto for axial translation, or to release it in order to release the bar therefrom;

Itis obvious that with such a device it is possible to apparent from the following detailed description, to-

3,lill,tll9 Patented Aug. 20, 1963 machine the parts correctly, without whipping or fiexure of the bar from which they are taken, to effect the successive feed of the bar in a precise manner and to eject the machined parts automatically without recourse to devices designed specially for this purpose.

Other objects and advantages of the invention will be gether with the accompanying drawings submitted for purpose of illustration only and not intended to limit the scope of the invention.

In these drawings:

FIGURE 1 is a diagrammatic View, in perspective, of a copying lathe, equipped with apparatus according to the invention.

FIGURE 2 is a section through the apparatus on a longitudinal horizontal plane, along IIII, FIGURE 1.

FIGURE 2a is a section through the free wheel mechanism along line IIaIIa in FIG. 4.

FIGURE 3 is a section on a larger scale showing in more detail the distributor for the control liquid for the.

apparatus.

FIGURE 4 is a section on IVIV, FIGURE 2. FIGURE 5 is a section on V--V, FIGURE 2. FIGURE 6 is a diagram showing a cycle of operations which can be carried out with the apparatus according to.

the invention.

In known lathes adapted for operating on a bar, the latter passes through a hollow headstock and is held at the end by a tailstock.

The apparatus according to the invention, which is illustrated in FIGURES 1 to 5, is substituted for the tailstock.

'Ine body 1 of the apparatus comprises a bore guiding a sliding sleeve 2., which does not rotate and in which is centred, by means of bearings 3 and a double-thrust roller bearing 4-, a rotating spindle 5 which participates in the sliding movements of the sleeve 2. The front end of the spindle 5 car-ties the body 6 of a hydraulically controlled chuck, the arrangement of which will be described below. At its other end, the spindle 5 is provided with splines '7 by means of which it engages with a hollow rotary shaft 8.

At the rear of the body .1 there is fixed a plate 9 to which is secured a sleeve It surrounding the hollow shaft 8 and provided, at its front portion, with a shoulder 11 which, with a rear partition 12 integral with the sleeve 2, bounds an annular chamber 13. Between the partition 12 and the plate 9 there is provided an annular chamber 14 having a larger cross-section than that of the chamber 13.

The plate 9 serves as a support for a casing 15 enclosing the mechanism for driving the hollow shaft 8 in rotation. This shaft is centred in bearings 16, one pair of the bearings being supported by the casing 15 the other pairot bearings being supported by a plate 17 which is rigidly connected to the casing 15 and to winch is fixed a plate 18 provided with a central aperture.

. Keyed onto the shaft 8 is a tree-wheel mechanism con: I

sisting of a sprocket 19 providedwith ramps 20' which cooperate, through rollers 21, with a ring or outer rotatable driving sleeve 22 provided with teeth 23 and centred,

by means of bearingszd, on the sprocket i9. More particularly, rollers 21 are .wedged in position to provide a 7 positive drive of 'sh aftvs when sleeve 22. turns in one direction. and becomes unwedged when sleeve 22. rotates in the opposite direction.

i The teeth 23 mesh with a pinion 2s (FIGURE-'4) mounted on a shaft 26 to which is also keyed a pinion 27 inmesh with a pinion 28, in turn mounted on a shaft 29 driven in'rotation by the shaft 30 of an electric motor 3-1 fixed to the casing 15.

The pinions 27 and 28 are accessible after the removal of the plate 18- and may be replaced by pinions of ditferent diameters in such a manner as to obtain speeds, 015 the spindle slightly diiierent from those of the lathe spindle.

The body dotthe'chuck is fixed to a flange 32 integral with the spindle 5 and, with the latter, boundsa cylinder 33 in which is displaced a piston 34 integral with a sleeve 7 35. By means of bell-crank levers 36, this piston con-' trols the radial movement of thesilides 37 supporting the v jaws 33.

' under-pressure is controlled by a distributor consisting 3 essentially of a fixed sleeve 49' which is centred in a support 50 and in which is displaced a slide 51, shown on a larger scale in FIGURE 3. V V

, Three annular grooves 52, 53 and '54 are provided on the periphery of the sleeve 459. The groove 52' is connected, on the one hand to an inlet conduit 55 for the liquid and on the other hand, through a passage 56, to

the chamber 13. For this purpose, the passage 56 leads into the bore of the body 1 of the headstock and supplies the chamber 13- through one OT'IlLOIC. longitudinal grooves'57 and radial apertures 58 provided in the sleeve 2. The groove 53 is connected, through a conduit 59m the chamber 14. The groove 54 is connected to a conduit 60 for the return of the liquid to the reservoir.

An'annul-ar chamber or is provided at the periphery cation; through :a passage 62, with the groove 53 which supplies the chamber---14J The chamber 61 is also in communication, depending on the position occupied by the slide, either through a passage 63 with the inlet groove 52 tor the liquid or through a passage 64 with the groove 54 for the evacuation of the fluid. Finally, the groove 52 is always in communication, through a conduit 65 provided in the slide 51, with an annular chamber 66.

It should be noted that in the mid position of the slide, illustrated in FIGURE 3, there isa slight over lapping between the chamber ol, on the one hand and the passages 63 and 64 on the other hand, which deterrn-inestwo losses of pressure 63:: and 64a, the importance of which will be explained below.

The slide 51 is connected, at one end, to the moving armature 67 of an electro-magnet 68, by means of a spring 69 (FIGURE 2).

At the, other end, the slide '51 is connected to a journected to a shaft '72 centred, at the front, in, a fixed sup 1 Port-73.

Mounted on the 7 of the slide 51. This chamber is always in communinal 70 centred in a fixed support 71 and in turn cona Keyed onto the shaft 72 are a stop 87 at the rear on the one hand and astop 88 carrying a threaded adjusting rod 89' at the front 'on the other hand. 7

. Other stops, identical to the stop 3%, but displaced angulai ly in relation thereto, may be provided, in any The stop 87 cooperates with a detent 96} which is rnounted on a pin 91 capable of sliding in a support 9-2 rigidly connected to the sleeve 2 and is restored to its rnid position under the influence of a spring 93. The free end of the pin 91 cooperates with the threadedadjusting rods 89 mounted on the stops 88.

The hydraulic control circuit comprises a pump 94 (FIGURE 2) which delivers liquid, taken from a reservoir 95, to a pipe .96 connected to the distributor inlet (FIGURE 3), the evacuation conduit of the distributor being connected through a pipe 9 7 to the reservoir 95.

"The pipes 95 and 97 are also connected, on -the one hand to a four-way'valve 9S Whichcontrols the, admission of the liquid to the cylinder79 (FIG. 5 controlling the rotation of the shaft '72, and on the other hand, to a four-way valve 99 which controls the admission of the fluid to the cylinder 33 controlling thechuck The'control of the feed and'r'eturn movements of the sleeve 2 supporting the spindle Sis e'fiected as follows:

In the position illustrated in FIGURE 2, the slide 51 rests, under the action of the pressure in the chamber 66 and by means of the journal 76, the shaft 72 and the stop. 87, on the detent 90 which abuts against the support 92 compressing the spring 93. The sleeve 2 is immobilized when ihB'flVO losses of pressure 63a and 64a (FIG- URE 3) create, in the two chambers 13 and 14, pressures which are inversely proportional to the efiective sec tionof said chambers. I

V The energizing' of the electro-magnet 68 has-the effect of displacing the slide 51 towards the right. =Thcloss of pressure 64a (FIGURE ,3) is eliminated and the liquid acts'with the same unitary pressure in the-chambers 13 and 14. The force exerted in the chamber l ibecomes preponderant and the sleeve Zis displacedforward's, that the chamber 14, and brings the latter into communication with the groove 54 for the return to the reservoir (FIG- URE 3). The pressure in the chamber 14 is reduced and the sleeve 2 tends to return to its initial position under the action of the pressure which is acting in the chamber 13. The spring 69 of the electro-magnet tends to restore towards the right'the slide 51 which is finally immobilized in the position in which the. forces in the two chambers journal 79 is a pinion 74 in mesh with I v .azrack 75. Asshown in FIGURE 5, the connection be tween the journallt} and the pinion 74 is eiiected by meansof a pawl76 subject to the action of a spring 77 and cooperating with ratchet teeth 78 provided'in the pinion in such a manner "as to drive; the journalfmv Y only, in one direction of rotation ofthe pinion 74/; The

constitiites 'a; plunger displaced in a cyl-inder 79 supp-lied withliq-uid underpressureat its two ends through is provided a safety system comprising a frusto-conical I cup 84 registered With a ball 35 housed in a recess provided a ring 86 rigidly connected to the support 7 i.

. .ing thesleeve-z in its rear position H a Since the feed strokeoffthe sleeve-2 isfdete'rrnined by" I the position of the stop 88, it is possible, by arranging 13 and 14 are in equilibrium, and the sleeve 2 is immobilized in apredetermined position. 7, 1

The return of the sleeve 2 to its hiitial position is controlled by the de-energizing of the electro-n iagnet 68. Under the action of the'liquid in the chambered,

the slide 51 is displaced 'toward s' thev left, bringing the .chamberl t into communication with the groovefid for evacuating the liquid. Thepressu're'd'ropsLin the charm: ber -14, and the action of theliquid, inthe. chamber '13;

restores the 'sleevejz' towai'ds the rear. When thedetent V comes into contactwitli-the stop 87, it drivesfthe slide 51 towardssthe right, interrupting the evacuation o'f. the

liquidand restoring the equilibrium "of forces in the chambers 13 and 14,whicli has the i f6il0f'll1lll1l6blliiZ-f a. plurality of stepson the shaft 72, to obtain-a plurality desired number, on the shaft '72, in firon-t' of the stop of the-valve 98 has the effect of driving the rack 75 r and consequently the pinion 74 which causes the shaft 72 to turn through the angle necessary to bring the adjusting rod 89 of the following stop 88 opposite the pin 91. Any accidental feed movement of the sleeve 2 during the rotation of the shaft 72 is prevented by a movement towards the left of the slide 51, bringing the chamber 14 into temporary communication with the. evacuation groove 54. This movement of the slide 51 is due to the fact that, during the rotation of the journal 70, the latter is urged forwards by the ball 85, against the action of the spring 69 of the electro-magnet, until the moment when the ball is oppositethe following cup 84 provided in the journal.

This safety device or system comprising the cup 84 and ball 85 is of the type described in the French patent application filed by the applicants on May 20, 1957, on

the No. PV 738,985 for Process and Device for Manipulating a Bar in a Lathe for Machining Parts From the Bar, now French Patent 1,175,542 dated November 17, 1958.

The arrangement of the apparatus described above, permits numerous cycles of operations to be carried out, particularly that defined below and shown diagrammatically in FIGURE 6.

In the following, it will be assumed that the energizing of the electro-magnet, the locking and release of the chuck and the angular movements of the shaft with the stops are controlled by manual operations. These various operations could be controlled automatically, depending on the positions occupied by the various moving members, by means of a conventional apparatus comprising, in particular, limit contactors, electrically operated valves etc.

In the position A in FIGURE 6, the jaws 38 of the mobile chuck are closed on the end of a part 100 previously machined but not yet separated from the rough bar 101. The jaws 102 of the headstock chuck of the lathe are closed on the bar 101 and drive it in rotation, together with the mobile chuck 6 which is then disconnected from its own drive by the action of the free wheel mechanism'and rotates at the speed given to this drive.

The traversing tool 103 and the parting oif tool 104 are shown in position for the start of the cycle.

When the traversing tool 103 has eflfected the machining of the bar 101 over a given length (position B), the parting-ofi tool 104 separates the part 100 from the bar (position C); the free wheel mechanism is clutched and the parting-off tool removes the stub ends from the two separated members driven independently of one another.

After the withdrawal of the parting-01f tool, the jaws 38 of the mobile chuck are opened, by reversing, the liquid been machined, the successive advance movements of the sleeve being controlled by the suitably spaced stops on the bar 72 and brought into action successively by the periodic rotations of the said bar (positions E and F).

At the end of the last traversing operation, the jaws 102 of the spindle chuck of the lathe are opened (position F) and the de-energizing of the electro-magnet then causes the return of the closed mobile chuck 38, to its initial position (position A) taking the bar with it, the distance of the return travel being determined eX-aotly by the hydraulic locking of the sleeve. The end of the bar which has already been parted off has come into contact with the part previously machined and pushed it back towards the rear of the apparatus, on leaving which the parts can be collected one after the other.

The invention is in no way limited to the embodiment described and illustrated; it is capable of numerous modifioations, available to one skilled in the art, without departing from the spirit of the invention as defined by the following claim-s.

What I claim is:

1. In a machine tool having a head stock provided With a rotary chuck for holding a work piece and a tool slide structure, a tail stock including a rotary and axially movable hollow spindle adapted to receive said work piece, a gripping device carried by said spindle and including radially movable work-engaging members, and means for operating said gripping device into and out of operative position, the improvement comprising fluid-operated means to move said, spindle lengthwise toward and away from said chuck, a valve mechanism including a movable valve actuating element for controlling the flow of fluid toward and from said fluid operated means, a stop member mounted on said spindle, a rotatable and axially movable shaft operatively connected with said valve actuating element for axial movement therewith, a plurality of axially and circumferentially spaced abutment members on said shaft, and means to rotate said shaft so as to move said abutment members into successive alignment with said stop member to thereby establish predetermined limits of advance movement of said spindle and consequently of said gripping device toward said chuck.

, from said chuck, a valve mechanism including a movable pressure in the chuck by meansof the valve 99 actuated by the bar.

any suitable means and the energizing of the "electr'omagiiet 68 causes the advance of the sleeve as far as the first stop provided on the shaft 72; when the sleeve has been hydraulically locked in thispositiomthe chuck 38 is again closed on the portion whichhas just been machined, and f supports the bar in the vicinity of the traversing tool, (posi tion D). It will be noted that the circumferential slip between the bar 191 andthe jaws of the chuck 38 fis very} slight at the moment when the jaws are closed because the? chuck is driven in rotation at. a speed similar to-thatof In the same mannen after each traversing operation, the,

mobile chuck is locked onto the portion 'which has just" valve actuating element for controlling the flow of fluid toward and from said fluid operated means, coordinated abutment means on said spindleand said valve actuating element effective to establish predetermined limits of advance movement of said spindle toward said chuck, a motor, a driving connection between said spindle and said motor for rotating said spindle by said motor, and a free Wheelmechanism in said-driving connection; r 3. In a machine tool having a head stock provided with a rotary chuck for releasably holding a piece of work, a

tail stock, and atool slide structure between said head stock and said tailstock, the improvement comprising-a rotary and fiaXlHllY movable .hollowspindle in said tail stock adapted to receive said workpiece, a gripping device carried by said spindle and including radially movable work engaging Inenibers to grip. and support said WOl'k-. piece, a fluid-dperated means to inove said spindle lengtln r wise toward and away fromsaid- 'chi 1 ck, a valvemechanism for. controlling the .flow'of fluidtoward and from said fluid-operated means, means for operating; said gripping devicefinto -and out of operative position, and control meahs for said valve mechanism for causing said spindle to move vtoward said chuck when the latter holds said piece 0 f Work and said gripping device is in inoperative position, and for causin g said spindle to move away from said chuck when said gripping device is in operative position and said 5 piece of Work released from said chuck.

References Cited in the file of this patent UNITED STATES. PATENTS Davenport June 6, 1933 Slovak June 5 1945 Robichaud July 17, 1951 

1. IN A MACHINE TOOL HAVING A HEAD STOCK PROVIDED WITH A ROTARY CHUCK FOR HOLDING A WORK PIECE AND A TOOL SLIDE STRUCTURE, A TAIL STOCK INCLUDING A ROTARY AND AXIALLY MOVABLE HOLLOW SPINDLE ADAPTED TO RECEIVE SAID WORK PIECE, A GRIPPING DEVICE CARRIED BY SAID SPINDLE AND INCLUDING RADIALLY MOVABLE WORK-ENGAGING MEMBERS, AND MEANS FOR OPERATING SAID GRIPPING DEVICE INTO AND OUT OF OPERATIVE POSITION, THE IMPROVEMENT COMPRISING FLUID-OPERATED MEANS TO MOVE SAID SPINDLE LENGTHWISE TOWARD AND AWAY FROM SAID CHUCK, A VALVE MECHANISM INCLUDING A MOVABLE VALVE ACTUATING ELEMENT FOR CONTROLLING THE FLOW OF FLUID TOWARD AND FROM SAID FLUID OPERATED MEANS, A STOP MEMBER MOUNTED ON SAID SPINDLE, A ROTATABLE AND AXIALLY MOVABLE SHAFT OPERATIVELY CONNECTED WITH SAID VALVE ACTUATING ELEMENT FOR AXIAL MOVEMENT THEREWITH, A PLURALITY OF AXIALLY AND CIRCUMFERENTIALLY SPACED ABUTMENT MEMBERS ON SAID SHAFT, AND MEANS TO ROTATE SAID SHAFT SO AS TO MOVE SAID ABUTMENT MEMBERS INTO SUCCESSIVE ALIGNMENT WITH SAID STOP MEMBER TO THEREBY ESTABLISH PREDETERMINED LIMITS OF ADVANCE MOVEMENT OF SAID SPINDLE AND CONSEQUENTLY OF SAID GRIPPING DEVICE TOWARD SAID CHUCK. 